Western Well Tool (WWT) has designed and produced a variety of non-rotating drill pipe protector assemblies that are used in drilling and completion work in oil and gas wells, as shown in U.S. Pat. No. 5,069,297; U.S. Pat. No. 5,579,854; U.S. Pat. No. 5,833,019; U.S. Pat. No. 6,250,405; U.S. Pat. No. 6,378,633; and U.S. Pat. No. 6,739,415, all of which are incorporated herein by this reference.
As part of the process to increase the utility of these non-rotating drill pipe protector assemblies, variations of the design can incorporate features that facilitate its use for a particular application, such as torque reduction, casing wear prevention, drag reduction, buckling load improvement, and pipe centralization within the casing. As part of this expansion of non-rotating drill pipe protectors, it is desirable, when operating inside a large diameter pipe, to use a large diameter non-rotating protector assembly to help centralize the pipe within the casing, which may be curved along its length. For example, when running 6⅝ inch drill pipe inside 13⅜ inch to 20 inch pipe, the non-rotating drill pipe protector sleeve outside diameter is typically about 9 inches. However, greater centralization within pipe is achieved when the sleeve diameter is increased to 10 or 18 inches or larger.
In addition to reducing drag and providing centralization within casing, a large enough protector of appropriate density will displace wellbore fluid and reduce the effective weight of the drill pipe in fluid. This practice has application in both drilling and casing landing operations as string weights continue to increase with well depth.
However, increasing the diameter of the non-rotating drill pipe protector sleeve, without increasing of the associated stop collar that holds the sleeve in place, may result in a substantially unprotected protrusion that can be caught on various irregularities, restrictions and wellbore equipment within the hole. The result is the assembly could be caught on a surface, resulting in damage to the non-rotating drill pipe protector, the pipe, or both. To avoid such potential damage, it is advantageous to have a collar assembly that is slightly smaller than the sleeve, thus providing a protective surface for the sleeve. However, as the size of the sleeves increase, the size of the collars can increase to the point that installation is difficult due to the weight of the collars. In addition, the gripping of the large diameter collars is more difficult to achieve when the associated bolts are tightened during installation.
To allow the use of larger diameter sleeves and collars without excessive weight of the collars or sleeves, this invention provides a solution. In addition, it is recognized that it would also be advantageous in sleeve manufacturing to have elements encased in an outer coating, thus providing adjustable rigidity and/or density. A process has also been developed to manufacture sleeves with a multiplicity of inserts having improvements described below.